WO2019082740A1

WO2019082740A1 - Hot dry spraying material and method for hot dry spraying work

Info

Publication number: WO2019082740A1
Application number: PCT/JP2018/038510
Authority: WO
Inventors: 洋輔大野
Original assignee: 黒崎播磨株式会社
Priority date: 2017-10-25
Filing date: 2018-10-16
Publication date: 2019-05-02
Also published as: JP2019077590A; CN111164058A; TWI681941B; JP6408678B1; TW201922669A

Abstract

The purpose of the present invention is to improve adhesion, adhesiveness, and corrosion resistance in a hot dry spraying material and a method for hot dry spraying work. To this end, the present invention is a method for hot dry spraying work in which a formulation comprising a refractory material and a binder is pressure-fed through a tubing toward a spray nozzle, water is added at a distal end section of the spray nozzle, and same is hot-sprayed on, wherein the method is characterized in that the formulation comprises 10 to 50 mass% magnesium limestone having a grain size of 1 mm or larger out of 100 mass% of the total amount of the refractory material and the binder, and the amount of water added is 10 to 50 mass% in terms of outer percentage relative to the 100 mass% of the total amount of the refractory material and the binder.

Description

Hot-use dry spray material and hot-dry spray construction method

TECHNICAL FIELD The present invention relates to a hot-use dry spray material (amorphous refractory) which is suitably used for hot repair of an industrial furnace such as a molten steel pan and a furnace body (furnace wall) of an electric furnace, and a construction method thereof.

In the case of monolithic refractories, the construction method differs depending on the use application. For example, when a monolithic refractory is used as a castable material for lining of an industrial kiln, construction is carried out through a kneading step of a refractory material and water, a pouring step, a curing step, and a drying step.

On the other hand, there are also cases where a monolithic refractory is used as a construction material for industrial kilns or as a spraying material for repair. In this case, the construction method is roughly classified into a wet spray construction method and a dry spray construction method. In the wet spraying construction method, the spraying material and water are sufficiently kneaded in advance by a mechanical kneading mechanism such as a mixer, and the kneaded mixture is pumped by a pump toward a spraying nozzle, and the tip of the spraying nozzle Air and a quick-setting agent are introduced and sprayed. The dry spraying construction method is a construction method in which water is added to the dry powder-like spraying material at the tip portion of the spraying nozzle without using a mechanical kneading mechanism, and spraying is performed.

In general, the spray application using a spray material is performed in both hot and cold environments, and the dry spray application method is applied in both environments. However, the wet spray application method is not generally applied in a hot environment. In the case of the wet spraying construction method, it is necessary to perform a post-kneading operation such as a cleaning operation of a transfer hose used when pressure-feeding with a kneader or a pump after the construction, since a preliminary kneading operation is necessary. Therefore, a wet construction method is not suitable for spray construction under a hot environment, and a dry construction method, which is a simple construction method, is often applied.

The spraying material (amorphous refractory for dry spraying) used in this dry spraying construction method is the adhesion between the spraying material and the surface to be constructed at the time of spraying and the spraying material after the industrial kiln operates after spraying. It is necessary to improve the adhesion to the work surface and the corrosion resistance of the spray material.

Patent Document 1 discloses a spray material containing magnesia limestone as a monolithic spray refractory for dry spraying. However, when the inventors of the present invention performed a hot spray application using a spray material containing magnesia limestone, there were cases where adhesion, adhesion and corrosion resistance were not sufficient.

JP-A-58-145660

The problem to be solved by the present invention is to improve adhesion, adhesiveness and corrosion resistance in a hot dry spraying material and a hot dry spraying application method.

According to one aspect of the present invention, the following dry-type hot-spraying material is provided.
"A dry-type hot-spraying material containing a refractory material and a binder,
10% by mass or more and 50% by mass or less of magnesia limestone having a particle diameter of 1 mm or more in the total amount of 100% by mass of the refractory material and the binder
The dry-type hot-spraying material for hot formed by adding 10 mass% or more and 50 mass% or less water by the external weight with respect to the total amount 100 mass% of the said refractory material and the said binder. "

According to another aspect of the present invention, the following hot dry spray application method is provided.
"In a hot dry spray application method, a composition containing a refractory material and a binder is pressure-fed through a pipe toward a spray nozzle, water is added at the tip of the spray nozzle, and the spray is performed hotly.
The composition contains 10% by mass to 50% by mass of limestone having a particle diameter of 1 mm or more in a total amount of 100% by mass of the refractory material and the binder.
The hot dry spray application method, wherein an addition amount of the water is 10% by mass to 50% by mass with respect to a total amount of 100% by mass of the refractory material and the binder. "

ADVANTAGE OF THE INVENTION According to this invention, adhesiveness, adhesiveness, and corrosion resistance can be improved by making content of a limestone and water of 1 mm or more into a specific range. Specifically, as the effect of improving adhesion and adhesion, first, water volatilizes to form open pores in the construction of the spray material, and thereafter, magma limestone having a particle diameter of 1 mm or more is decomposed to form carbon dioxide gas. The carbon dioxide gas generates open pores. That is, quick drying is obtained by the path | route which penetrates a construction body by two steps is produced | generated. Thereby, dehydration from the interface between the construction body (spraying material) and the construction body is promoted, and adhesion and adhesiveness are improved.

It is explanatory drawing which shows the evaluation method of adhesiveness.

The dry spray material for hot use of the present invention contains 10% by mass to 50% by mass of limestone having a particle diameter of 1 mm or more in 100% by mass of the total amount of the refractory material and the binder (hereinafter referred to as "total amount"). 10 to 50% by mass of water is externally added to the total amount of 100% by mass.

Muddy limestone (CaCO ₃ · MgCO ₃ ) having a particle diameter of 1 mm or more generates carbon dioxide gas (CO ₂ ) by the decomposition reaction of the following formula (1).
CaCO ₃ · MgCO ₃ → CaO · MgO + 2CO ₂ ... (1)
The decomposition reaction starts at about 600 ° C. and ends at about 800 ° C. Therefore, when the hot-use dry spraying material of the present invention is sprayed by hot spraying, as described above, water volatilizes first to form open pores in the coating material of the spraying material, and thereafter, a mammite having a particle diameter of 1 mm or more Limestone decomposes to generate carbon dioxide gas, which generates open pores. As a result, adhesion and adhesiveness can be improved. The term "hot" refers to an environment in which the temperature of the work surface is approximately 600 ° C or higher.

If the content of the limestone having a particle diameter of 1 mm or more is less than 10% by mass, the effect of improving adhesion and adhesion can not be sufficiently obtained. On the other hand, if the content of the limestone having a particle diameter of 1 mm or more exceeds 50% by mass, the amount of carbon dioxide gas generated by the decomposition reaction is too large, and the adhesion and the adhesiveness are lowered. In addition, the number of pores generated by carbon dioxide increases and the corrosion resistance also decreases. It is preferable that content of the magma limestone with a particle diameter of 1 mm or more is 20 mass% or more and 40 mass% or less in 100 mass% of total amounts.

The dry hot-spraying material of the present invention may contain magnesia limestone having a particle size of less than 1 mm. However, if a large amount of limestone with a particle size of less than 1 mm is included, the decomposition reaction (Formula (1)) of the limestone with a particle size of less than 1 mm occurs immediately after adhesion to the work surface. Ca ²⁺ elutes in the construction body by the hydration reaction of CaO (the following formula (2)). As a result, the viscosity of the slurry-like construction body increases at an early stage, and there is a concern that the wettability to the work surface can not be ensured and the adhesion is reduced due to the curing. Therefore, it is preferable that content of less than 1 mm of particle diameters of limestone with a particle size is 25 mass% or less (0 is included) in 100 mass% of total amounts.
_{^{CaO + 2H 2 O → Ca 2+}} + 2OH - ... (2)

In the present invention, as described above, the addition amount of water at the time of spray construction is 10% by mass or more and 50% by mass or less on the basis of the total amount of 100% by mass. When the addition amount of water is less than 10% by mass, the spray material and the water are not sufficiently mixed and the spray construction can not be established. In addition, since the amount of water is low and the water volatilizes immediately because of the small amount of water, heat is easily transmitted to the construction body, and the decomposition reaction of mafic limestone having a particle diameter of 1 mm or more is too fast, and the formation of carbon dioxide gas is too fast. As a result, the adhesion and adhesiveness decrease.
On the other hand, when the added amount of water is more than 50% by mass, excessive open pores are generated by the open pores generated by volatilization of water and the open pores by carbon dioxide gas generated from magnesia limestone having a particle diameter of 1 mm or more. Corrosion resistance is reduced.
It is preferable that the addition amount of water is 20 mass% or more and 40 mass% or less by external weight with respect to 100 mass% of total amounts.

The dry-type hot-spraying material of the present invention may include various refractory materials generally used for the spraying material as a refractory material other than magnesia limestone, but the main body is considering the compatibility with magnesia limestone. It is preferable to use a basic refractory material (basic oxide) such as magnesia, olivine (olivine), or used magnesia-carbon brick waste. The refractory material other than the basic refractory material may include alumina and the like.

As the binder, those generally used in dry-type spray materials can be used as a binder, and examples thereof include silicates such as sodium silicate, phosphates, pitch, powder resin, alumina cement and the like. Further, the amount (content) of the binder used may be the same as that of a general dry-type spray material, and is, for example, 1% by mass or more and 10% by mass or less in 100% by mass in total.

In addition, an additive may be used for the binder. As the additive, various additives such as a curing agent, a dispersing agent, and a thickener can be used. For example, slaked lime as a curing agent, phosphate as a dispersing agent, and clay as a thickening agent can be used.

The above-described dry-type hot-spraying material for hot working of the present invention feeds a composition containing a refractory material and a binder as described above toward a spray nozzle through piping, and adds water at the tip of the spray nozzle. It is subjected to a hot dry spray application method of hot spraying.

Table 1 and Table 2 show the material configurations and evaluation results of the examples and comparative examples of the dry type hot-blasting material of the present invention. In Table 1 and Table 2, "others" of the binder is clay, slaked lime, a dispersant or the like.
The evaluation items and the evaluation method are as follows.

<Corrosion resistance>
The hot-use dry spray material of each example was sprayed from the spray nozzle at a spray rate of 15 kg / min toward the surface of the magnesia brick heated to 1000 ° C. as a work surface for 1 minute. At this time, the addition amount of water added at the tip of the spray nozzle was the amount shown in each example of Table 1 and Table 2. That is, the "added amount of water" shown in Tables 1 and 2 indicates the externally added amount with respect to the total amount of 100% by mass.
By performing the spraying for 1 minute, a sprayed construction body including a construction body of a 50 mm-thick spray material was obtained. Using a rotary erosion tester, a sample of a predetermined size cut out from the spray construction body was corroded at 1650 to 1700 ° C. for 3 hours using a converter slag of C / S = 3.5 as the corroding agent. The maximum amount of melting loss in each case was measured, and the relative amount was determined, where the maximum amount of melting loss in Example 1 was 100. The case where the relative amount was 100 or less was evaluated as ◎ (excellent), the case where it was over 100 and under 110 as ○ (good), and the case where it was over 110 as x (not good).

<Adhesiveness>
In the sprayed construction bodies of each example obtained in the above-mentioned manner, the shear stress between the construction body of the sprayed material and the magnesia brick is measured, and the relative value with the shear stress of Example 1 being 100 is determined. The case where が was 100 or more was evaluated as ◎ (excellent), the case of over 70 and less than 100 as ((good), and the case of 70 or less as x (impossible).

<Adhesiveness>
As shown in the upper part of Fig. 1, a 15 mm gap is provided at the center of the magnesia brick in the shape of a european, between which the water corresponding to the added amount of water is added and kneaded into the spray material of each example. After drying, as shown in the lower part of FIG. 1, the test piece was fired at 1400 ° C. for 3 hours while applying a load of 0.25 MPa from the tip of the yoke. The bending strength of the adhesive surface of the test pieces of each example was measured by a 3-point bending test to obtain a relative value with the bending strength of Example 1 being 100, and ◎ (excellent) when the relative value was 100 or more. The case of 60 or more and less than 100 was evaluated as ○ (good), and the case of 60 or less as x (not possible).
The evaluation of the adhesive property is an index representing the adhesive strength between the sprayed material and the work surface after the industrial kiln operates after the spraying in an actual spray construction.

<Overall evaluation>
In each of the above evaluations, when 優 is 2 or more, ◎ (excellent), when が is 2 or more as として (good), and when any one is x and when measurement is not possible is x (impossible) Three grades were evaluated. This comprehensive evaluation is an index that represents the durability of the actual spray construction body.

Examples 1 to 11 shown in Table 1 are hot dry spray materials within the scope of the present invention. In all cases, the overall evaluation was 優 (excellent) or ((good), and good results were obtained.

Comparative Example 1 in Table 2 is an example in which the content of mafic limestone having a particle size of 1 mm or more is small. Adhesiveness and the improvement effect of adhesiveness were not fully acquired, but evaluation of adhesiveness and adhesiveness became x (improper). Comparative Example 2 is an example in which the content of the limestone having a particle diameter of 1 mm or more is large. The amount of carbon dioxide gas was too much, and the adhesion and adhesiveness decreased, and the corrosion resistance also decreased.

Comparative Example 3 is an example in which the amount of water added is small. It became impossible to measure because the spray construction was not established. Comparative Example 4 is an example in which the amount of water added is large. There were too many open pores and corrosion resistance fell.

Comparative Example 5 is an example in which calcined limestone is replaced by calcined dolomite. It became impossible to measure because calcined dolomite has strong digestibility. Comparative Example 6 is an example in which limestone is used instead of magma limestone. Corrosion resistance decreased because limestone (CaCO ₃ ) forms a low melting point compound.

Claims

What is claimed is: 1. A dry-type hot-pressing material comprising a refractory material and a binder;
10% by mass or more and 50% by mass or less of magnesia limestone having a particle diameter of 1 mm or more in the total amount of 100% by mass of the refractory material and the binder
The dry-type hot-spraying material for hot formed by adding 10 mass% or more and 50 mass% or less water by the external weight with respect to the total amount 100 mass% of the said refractory material and the said binder.
The dry spray for hot according to claim 1, wherein the content of the muddy limestone having a particle diameter of less than 1 mm is 25% by mass or less (including 0) in the total amount of 100% by mass of the refractory material and the binder. Material.
In the total amount of 100% by mass of the refractory material and the binder, the content of the limestone having a particle diameter of 1 mm or more is 20% by mass or more and 40% by mass or less.
3. The dry-type hot-pressing material according to claim 1, wherein an addition amount of the water is 20% by mass to 40% by mass with respect to a total amount of 100% by mass of the refractory material and the binder.
In a hot dry spray application method of pressure-feeding a composition containing a refractory material and a binder toward a spray nozzle through piping, adding water at the tip of the spray nozzle and spraying hotly
The composition contains 10% by mass to 50% by mass of limestone having a particle diameter of 1 mm or more in a total amount of 100% by mass of the refractory material and the binder.
The hot dry spray application method, wherein an addition amount of the water is 10% by mass to 50% by mass with respect to a total amount of 100% by mass of the refractory material and the binder.